Engine crankcase and filler device



y 3 J. c. SLONNEGER 2,638,076 7 ENGINE CRANKC'ASE AND FILLER DEVICE Original Filed March 14, 1946 Patented May 12, i953 UNITED STATES PATENT 'O'F'FI'CE ENGINE CRAN'KCASE AND FILLER DEVICE John G. Slcnneg'cr, Dallas, Tom, assignor to The Continental Supply Company, Dallas, Tom, a corporation of Delaware Original application March 14, 1946, Serial No. 654,427. Divided and this application January 5, 1948, Serial No. 637

2 Claims. (01. 121-494) This invention relates to new and usetul improvements. in breather systems tor internal combust-ion engines.

One object of the invention is to provide an improved breather system particularly adapted to, but not limited to, onecyl inderinternal combustion engines.

A particular object of the invention is to provide an improved system, wherein the breather is open to the atmosphere only during the outer or bottom dead center portion of the crank shaft cycle and is closed to the atmosphere during the remainder of said cycle, whereby the loss of lu'b ricating oil from the engine is substantially eliminated.

An important object of the invention is to provide an improved system wherein the lubricating oil entrained with the air escaping through the breather is trapped and permitted to drain or flow back into the crankcase and is thus con- Served.

Another object of the invention is to provide an improved breather system which includes an enclosure having a vent to the atmosphere; an air. passage to a crankcase and a, movable momher having. means periodically opening and clos- .ing said passage, whereby an air stream may flow through said passage only during a minor portion of the cycle of revolution of the engine crankshaft.

Still another object of theinvention is to provide an improved breather system which includes an enclosure having a vent to the atmosphere, and air passage to a crankcase, means in the enclosure for setting up whirling of the air therein whereby oil particles are separated from the air in said enclosure.

A further object of the invention is to provide a system wherein the breather is combined with the engine governor, whereby oil entrained in the air is separated from the latter and utilized to lubricate the governor, the surplus oil being drained or conducted back to the crankcase.

Another object is to provide in connection with the system, a filling device arranged so that addi tional oil may be introduced into the crankcase, while the engine is operating, without drawing sufficient air into said case through the device to disrupt the breather system.

A construction designed to carry out the invention will be hereinafter, described together with other-features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, wherein an example of the invention is shown, and wherein:

1 is a vertical section view through the top of the crank and governor of an internal combustion engine, illustrating a breather sys- 2 tem constructed in accordanc with the inven tion.

Figs. 2, 3 and t are transverse sectional views taken on their respective lines of Fig. 1 and look-+ ing in the directions of their arrows, and 1 Fig. 5 is a vertical sectional view of the airexcluding oil filling device.

This application is filed as a division of my co-pcnding application filed March 14, 1946, Serial No. 654,427, now Patent No. 2,590,134.

In the drawings, the numeral ll! designates the top wall of an internal combustion-engine crankcase H. The upper end of the camshaft l 2 terminates just below the wall A d and has a horizontaliy disposed gear 3 fastened thereon. This gear drives a pinion M secured on the lower reduced shame 35 of a tubular governor shaft It. The governor shaft is supported in a horizontal ball bearing assembly l"! which is mounted in a.

collar 18. The collar fits snugly in a circular opening 19 and depends from a governor base 253 which is bolted on the wall iii.

The governor includes a dome-shaped housing 2i which is secured in a recess 22 by bolts '23. The base is flanged and has a vertical bore 2% which is a continuation of the bore or the collar IS. The upper end of the shaft it is-shouldered and has the hub 25 of a. grooved bracket 26, fastened thereon. The hub has a free rotating fit in the upper end of thebore 2t. Itis pointed out that oil accumulating in the bottom of the housing 2i may drain or flow into the bore '24 around the hub 25, thence down through said bore 130 the assembly IT which will thus be lubricated. Since the lower end of the collar it is open to the crankcase, surplus oil may drain or flow into said case.

Angular governor arms 27' are mounted in the grooved bracket 26 on pins 28 and carry the usual weights 29 at the upper ends. These weights overhang fingers 3i extending inwardly in the grooved bracket and tend to swing the arms inwardly. A plunger 3| is mounted to slide vertically in the upper end of the shaft H3 and a disk head 32 which overhangs the fingers 3d. The governor operates in the usual manner,

whereby the weight arms are swung outwardly as the speed of rotation increases, which causes the fingers to raise the plunger 3!. A cup 33 is secured on top of the plunger head and re ccives a ball 34 on which the lower end of a detent 35 is spindled. The upper end of the detent is journaled in a socket 36 which is suit ably mounted on the end of the arm 3! of a regulator, which will not be described since it is not a part of the invention.

A nipple 38 is secured in the ing 2| and carries a vent cap 39 which opens the housing to the atmosphere and permits air to escape from the housing. The base 29 has a top of the housa vertical chamber 4i formed at one side of the base. This chamber has an annular recess &2 at its lower end which receives the upper end of a flanged bushing 43, secured in an opening M in the crankcase wall I0. A nipple t has a sliding fit in the bushing and extends into the chamber.

The bottom of the nipple is flat so as to ride on the upper flat surface of the gear l3 and is provided vents its from being forced upwardly through the bushing. The gear has diametrically opposite ports 41 located to register with the bore of the nipple 45 at each half rotation of the gear. Anannular groove 48 is formed in the under side of the gear I3 and the ports 4'! extend from this groove which is constantly open to the crankcase. From the foregoing, it will be seen that communication between the crankcase and the interior of the housing is set up by way of the groove 48, ports 47, nipple 45, chamber 4| and port 40 when the ports 4'! are momentarily in registration with the bore of said nipple, and such communication is shut off when the ports are out of registration with the bore of the nipple.

It is pointed out that the camshaft I2 is timed to rotate once to every two revolutions of the crankshaft of the engine (not shown). The parts are so related and the ports 5! so positioned that each time the crankshaft reaches its outer or bottom dead center, one of the ports M of the gear I3 is in registration with bore of the nipple 45 and the crankcase is in communication with the atmosphere. The design and sizes of the elements are such, that each port 4! begins to open at approximately 15 before dead center and completes closing at approximately 15 after-dead center. These figures are merely illustrative and the invention is not to be limited thereto.

The result of the foregoing arrangement is that during more than 300 of the revolution of the crankshaft, the crankcase is shut off from communication with the atmosphere, and that such communication is established for a period having a duration of less than 60 of said revolution. As pointed out, this period of communication occurs during the time the piston is at, or very near, its lowermost point within the cylinder, or the point commonly referred to as bottom dead center. By reason of the laws of harmonic mo tion, the actual longitudinal movement of the piston, as the crankshaft revolves from 15 or 20 in advance of bottom dead center to 15 or 20 following bottom dead center, is very slight so the breathing structure described commences to.

open. However, at this point, the pressure within the crankcase has very nearly returned to that of the atmosphere due to the compressive action of the piston. As the piston approaches and reaches bottom dead center, a very small amount of the gases within the crankcase may pass outwardly through one of the ports 47. Similarly,

as the piston passes bottom dead center and begins to move toward the head of the cylinder, a very small amount of air may be drawn into the crankcase before the port is closed. For all practical purposes, the flow of air or gases, in and out, during this period may be disregarded because the degree of piston travel is actually very slight,

as previously pointed out. However, there is an additional factor which must be considered, and

with an annular flange ifi which prethat i blow-by of the combustion gases from above the piston. No matter how well the engine is constructed, there will be a very slight amount of the combustion gases which will escape past the piston rings into the crankcase, and the major portion of the gases which flow through the ports M is constituted by :such escaped combustion gases. Again, the quantity or volume of gas involved is very small so that only a low velocity is obtained as such gases pass upwardly through the bore of the nipple 45. The duration of the flow is relatively short since the ports are exposed for only a short period of time and also since only a very slight amount or volume of gas is present for disposal.

Thus, for more than 300 of the revolution of the crankshaft, there is a partial Vacuum in the crankcase, whereby the pressure in the case is lower than atmospheric pressure. Conversely, durin less than 60 of the revolution of the crankshaft, a pressure equal to or slightly greater than that of the atmosphere prevails in the crankcase. 'As pointed out, during this latter period of increased pressure in the crankcase, a small volume of air or gas is caused to flow from the crankcase through one of the ports 41. Such gas, in flowing from the crankcase, will carry a certain amount of mechanically entrained oil into the housing 2 i.

Owing to the larger area of the housing, the.

small volumeair or air or gas undergoes expansion and the velocity of the stream is reduced. The centrifugal action set up by the governor arms 2! will whirl the air or gas, whereby the oil particles will be thrown outwardly and will accumulate on the cylindrical wall of 'the housing. Therefore, the oil is not only separated from the air, but it is-trapped in the governor housing. Since the vent nipple .38 is comparatively small and since the ports 41 are closed during the major portion of the cycle of revolution of the crankshaft, ampletime will be given to separate the oil from the air in said housing.

As hereinbefore pointed out the separated and trapped oil may drain into the bore 24 of the housing 20, lubricate the shaft l6 and bearing assembly H and return to the crankcase. A surplus of oil will flow down through the port 40 into the chamber M, pass down around the nipple it and lubricate the surface of the gear l3 and the teeth of the pinion hi before returning to the crankcase.

It is pointed out that the flow of oil downwardly from the governor housing into the crankcase is encouraged and facilitated by reason of the operation of this engine breathing device. The crankcase is under a partial vacuum for a major portion of each revolution of the crankshaft and carries a pressure equal to or slightly greater than atmospheric for only a short portion of each such revolution. Thus, during a major portion of the engines running time, there will be a vacuum present within the crankcase tending to draw any displaced oil back into the case. The degree of vacuum obtained is sufficiently high to cause the oil to overcome capillary attraction or surface tension and flow from between the surfaces of the various elements of the governor, such a the bushing 43 and the nipple 45. However, the pressure above atmospheric obtained during the minor portion of the cycle is not of suflicient magnitude or of sufiicient duration to cause the oil to again flow upwardly into the governor structure. Thus, the breathing device becomes substantially unidirectional in so far as the return of oil to the crankcase is concerned. The forces tending to return the oil are of much longer duration and are greater than those forces tending to force the oil away from the crankcase. The net result is that oil passing into the governor housing along with the relatively small flow of air or gas thereinto, is ultimately all returned to the crankcase so that substantially no loss or dissipation through the breather cap 39 occurs.

An additional advantage of this predominance of a partial vacuum within the crankcase rather than a slight pressure above atmospheric is the prevention of escape of oil through the various joints and openings normally present in any crankcase. In this manner, the escape of oil past the oil seal rings around the crankshaft and other joints which may not be air tight, such as screw-threaded joints and the like, is prevented. In addition, the unidirectional action of this breather prevents power loss by eliminating the pumping of air in and out of the crankcase and furthermore avoids the contamination of the crankcase oil by foreign matter drawn in from the outside by said pumping of air in and out of the crankcase.

To implement further the desirable results obtained by this vacuum-maintaining breathing structure, a device is provided whereby oil may be added to the crankcase while the engine is operating without disrupting the breather system by the admission of additional air from the atmosphere. Such a device is shown in Fig. 5 and includes a collar 50 having its lower end internally and externally screw-threaded. The lower end of the collar is screwed into the top wall In of the crankcase at a convenient location.

The usual filler cap 5| is removably mounted on the upper end of said collar and an elongate nipple 52 has its upper end screw-threaded and screwed intothe collar. A sleeve 53, larger than the nipple, telescopes said nipple and has its bottom closed and spaced from the bottom of the nipple. Thelmper end of the sleeve is spaced a short distance from the Wall i and said sleeve is providedfl lt its top and bottom, with spacer lugs 54 which are welded or otherwise secured to the nipple 'to support the sleeve thereon.

The sleeve and nipple form a U-tube trap, whereby an oil column or seal is provided in the spaces within and between said nipple and sleeve. Added oil will unbalance this trap and overflow the upper end of the sleeve into the crankcase. Due to this oil seal free air is prevented from entering the case when oil is added. In order to prevent fluctuations in the oil seal column which may, due to the variable pressures in the crankcase, reach amplitudes sufiicient to displace enough oil into the crank to break the seal, a small aperture 55 is made in the nipple 52 between the collar 50 and the upper end" of the sleeve 53. When the cap is in place, this aperture equalizes the pressure between the crankcase and the small body of air trappedin the nipple above the oil column therein, and,

since this trapped volume of air is small, the aperture may likewise be small and still effect the desired equalization of pressure. Without this vent, the resilience of the trapped body of air acts as a spring, which together with the mass of oil in the trap, forms an oscillating system having a natural frequency. When the frequency of the pressure changes within the crankcase approaches the natural frequency of the said air-oil oscillating system, the amplitude of oscillation may become great enough to throw some of the trapping oil into the crankcase. If this occurs, the oil seal will be aiiected because the height of the oil columns will be reduced, and when the cap 5| is consequently removed, the remaining oil in the trap may be sucked into the crankcase so as to defeat the oil seal by allowing air to enter. Since an engine may be operated at various speeds, it is very probable that at some speed the frequency of pressure changes within the crankcase will fall into synchronization as described. Therefore, the vent or aperture is a very important feature and has much to do with the operation of this breathing system. At the same time, the oil seal described is also very important in permitting the addition of lubricating oil while preventing the entry of air at the same time.

The foregoing description of the invention is explanatory thereof and various change in the size, shape and materials, as well as in the details of the illustrated construction may be made,

within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. In combination, an engine crankcase in which a variable pressure is exerted while the engine is running, and means for maintaining a. substantial seal of the interior of said crankcase against outside atmosphere while oil is being introduced into the crankcase, said means comprising, an elongate imperforate open-ended filling tube extending through a wall of the crankcase and having a generally vertically disposed portion projecting a substantial distance into the interior of the crankcase, an elongate imperiorate oil trap sleeve surrounding the vertical portion of the tube within the crankcase, the upper end of the sleeve being open and terminating in the interior of the crankcase, the lower end of the sleeve being closed, the open lower end of the tube being disposed a substantial distance below the open upper end of the sleeve, said sleeve containing oil at all timesand forming with the tube a crankcase seal against the outside atmosphere, and the tube having-a single small air vent in its wall within the crankcase and above the upper end of the sleeve.

2. The combination as set forth in claim 1, and a closure on the outer end of the filling tube.

JOHN C. SLONNEGER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,071,328 McCarty Aug. 26, 1913 1,801,953 Caminez Apr. 21, 1931 1,808,245 Middleton June 2,. 1931 1,844,297 Roberts Feb. 9,. 1932 2,041,070 Jones May 19, 1936 2,052,782 Mann Sept. 1,1936 2,407,622 Wells Sept. 10, 1946 2,409,532 Bentley Oct. 15, 1946 

